Stable dry cleaning compositions

ABSTRACT

CONCENTRATED DRY CLEANING COMPOSITIONS, HAVING A PH OF FROM ABOUT 6.5 TO ABOUT 9 AND CONSISITING ESSENTIALLY OF A DRY CLEANING SOLVENT CONTAINING FROM ABOUT 0.25% TO ABOUT 0.75% BY WEIGHT OF A COUPLING AGENT AND FROM ABOUT 20% TO ABOUT 60% BY WEIGHT OF AN ANIONIC DETERGENT COMPRISING THE MONOETHANOLAMINE SALT OF AN ESSENTIALLY PURE, BROAD CUT, LINEAR C8 TO C18 ALKYL BENZENE SULFONIC ACID; WEIGHT RATIOS OF DETERGENT TO COUPLING AGENT ARE AT LEAST ABOUT 80:1. THE CONCENTRATED COMPOSITIONS HEREIN EXHIBIT SATISFACTORY STABILITY AGAINST PHASE SEPARATION AND, WHEN DILUTED WITH ADDITIONAL SOLVENT AND EMPLOYED IN COVENTIONAL DRY CLEANING OPERATIONS, ACHIEVE IMPROVED DRY CLEANING PERFORMANCE.

United States Patent US. Cl. 252153 8 Claims ABSTRACT OF THE DISCLOSUREConcentrated dry cleaning compositions, having a pH of from about 6.5 toabout 9 and consisting essentially of a dry cleaning solvent containingfrom about 0.25 to about 0.75% by weight of a coupling agent and fromabout 20% to about 60% by weight of an anionic detergent comprising themonoethanolamine salt of an essentially pure, broad cut, linear C to Calkyl benzene sulfonic acid; weight ratios of detergent to couplingagent are at least about 80:1. The concentrated compositions hereinexhibit satisfactory stability against phase separation and, whendiluted with additional solvent and employed in conventional drycleaning operations, achieve improved dry cleaning performance.

CROSS-REFERENCE TO RELATED COMPOSITIONS Concentrated dry cleaningcompositions, which consist essentially of a dry cleaning solvent and ananionic deterget comprising the monoethanolamine salt of an essentiallypure, broad cut, linear alkyl benzene sulfonic acid, are disclosed in aconcurrently filed, copending application, Ser. No. 885,652, filed Dec.16, 1969, filed by Gordon W. Potter, Jr. and entitled Improved DryCleaning Compositions; the disclosure of said application is herebyincorporated by reference. The disclosed compositions achieve improveddry cleaning performance When employed in conventional dry cleaningoperations.

The invention herein is directed to providing similar compositions inconcentrated form, which concentrated compositions exhibit satisfactorystability against phaseseparation as well as (after dilution withadditional dry cleaning solvent) similarly improved dry cleaningperformance.

BACKGROUND OF THE INVENTION The invention herein relates generally toconcentrated detergent compositions for use in the dry cleaning offabrics.

In a conventional process of dry cleaning fabrics, the soiled fabricsare agitated in a volatile organic dry cleaning solvent which isrelatively immiscible with water. Such solvents are generally effectivefor the removal of grease and oil stains as well as dust, dirt, lint andthe like which commonly adhere to the fabrics and to the grease and oilthereon. The agitation is generally accomplished by inserting thefabrics into a perforated cylinder which is rotated in the solvent bath.The solvent is usually circulated by means of a pump through a filterwhich removes suspended soil particles; by means of recycling andfiltering, the solvent can generally be reused many times, and afterbecoming badly contaminated, can be distilled and used again. Aftersufiicient treatment, the fabrics are usually subjected to centrifugalaction to remove excess solvent and then placed in a rotating cylinderor drying cabinet wherein final traces of solvent are removed by acurrent of warm air.

To promote the removal of water-soluble soil, such as those caused byvarious foods and the like, from the ice fabrics, the solvent generallyincorporates small amounts of water and/ or a fatty acid soap or anorganic synthetic detergent. Detergents so employed include a variety ofanionic, nonionic, and cationic compounds. Many such detergents, besideshaving detersive qualities, also have absorbefacient characteristicswhich permit water (either added to the solvent or resulting frommoisture in the fabrics or in the dry cleaning system) to become finelydispersed throughout the solvent and to achieve better water-solublesoil removal. Unfortunately, however, many such detergents themselvesexhibit relatively low levels of water-soluble stain removal andrelatively high levels of fabric graying and often result innecessitating postcleaning spot removal; other detergents impartrelatively poor water-solubilizing properties to the dry cleaningsolvent, which can lead to the presence of excess water in thesolvent-detergent system and, subsequently, to irreparable damage towater-sensitive garments, e.g., woolens; still other detergents requirespecial additives or methods of incorporation into the solvent toprovide and maintain a homogenous emulsion or single-phase necessary topermit use of the dry cleaning composition with the filtration apparatusconventionally used in retail and industrial dry cleaning operations.

The detergents employed in the compositions disclosed in theabove-referenced Potter application have the advantage of generallyavoiding the above-noted problems and, further, provide compositionswhich achieve improved dry cleaning performance, i.e., improved fabriccleaning and reduced fabric graying. For economic and other reasons, itis highly desirable to market a concentrated dry cleaning compositionhaving high amounts of these detergents.

These concentrated dry cleaning compositions, however, are susceptibleto phase-separation, apparently due to the presence of water, which canlead to a multiplicity of problems which relate, for example, to themanufacture, storage, and shipment of the compositions, as well as totheir dilution and subsequent use, as described hereinafter.

Therefore, a concentrated dry cleaning composition, which is stableagainst phase-separation and which (after dilution) is filterable andachieves improved dry cleaning performance, is highly desirable.

Accordingly, it is an object of the invention herein to provide aconcentrated dry cleaning composition which is stable againstphase-separation.

It is another object of the invention herein to provide a stable,concentrated dry cleaning composition which, after dilution withadditional solvent, can be employed to achieve improved dry cleaningperformance.

Further, it is an object of the invention herein to provide a stable,concentrated dry cleaning composition which, after dilution withadditional solvent, provides a single-phase composition with improveddry cleaning performance.

BRIEF SUMMARY OF THE INVENTION These and other objects are achieved bythe invention herein which comprises a concentrated dry cleaningcomposition which consists essentially of a dry cleaning solventcontaining from about 20% to about 60% by weight of an anionic detergentcomprising the monoethanolamine salt of an essentially pure, broad cut,linear alkyl benzene sulfonic acid wherein the alkyl is a mixture ofalkyls having an average chain length of from about 8 to about 18 carbonatoms, and from about 0.25% to about 0.75% by weight of a couplingagent, wherein the weight ratio of the detergent to the coupling agentis at least about :1, and further, wherein the composition has a pHwithin the range of from about 6.5 to about 9.

The concentrated dry cleaning compositions of the invention aregenerally stable against phase-separation even under severe conditionsand, after dilution with a suitable chlorinated dry cleaning solvent,provide compositions which are filterable and which exhibit improved drycleaning performance.

Specifically, by employing a coupling agent in the concentrated drycleaning compositions herein, stability against phase-separation isachieved. By employing a detergent, comprising the above-describedmonoethanolamine salt of an essentially pure, broad cut, linear alkyl(from about C to about C benzene sulfonic acid (hereinafter alsoreferred to herein as MEA-LAS for brevity), the concentratedcompositions herein can be diluted with additional solvent to achieve ause level dry cleaning composition (i.e., a composition ready for directincorporation and use in dry cleaning operations) with improved fabriccleaning, i.e. insoluble and water-soluble soil removal, and reducedfabric graying, i.e. soil redeposition.

DETAILED DESCRIPTION OF THE INVENTION It has now been found that thepresence of water in a concentrated MEA-LAS dry cleaning composition(i.e., a composition concentrated with detergent and requiring dilutionwith additional dry cleaning solvent prior to its incorporation and usein dry cleaning operations) can lead to phase-separation in thecomposition. For example, experimental observations indicate that aslittle as about 0.3% by weight water in such concentrated dry cleaningcompositions containing about 40% by weight detergent generally causesphase-separation after a shelf-life of as little as three days.

It is believed that water present in the concentrated composition isintroduced during processing or manufacturing procedures and isparticularly carried over into the composition along with the detergentadditive. 'It is further believed that the water in the concentratedcomposition extracts or removes the detergent from the dry cleaningsolvent and otherwise prevents solubilization of the detergent in thesolvent. As a consequence, the composition exhibits two phases: anaqueous phase which contains at least a substantial amount of thedetergent being em ployed, an an organic phase consisting essentially ofthe dry cleaning solvent.

Problems resulting from phase-separation can be severe. For example,concentrated compositions, which have separated into aqueous and organicphases, generally exhibit unsatisfactory freeze-thaw stability andrecovery to a singe-phase; thus, such phase-separated compositions canundesirably require special procedures for their storage and/orshipment.

Moreover, detergent extracted into the water present in the concentratedcompositions generally does not satisfactorily redistribute orresolubilize in the solvent upon dilution of the concentratedcomposition; thus, sample portions of the resulting use levelcomposition generally exhibit dissimilar or inconsistent amounts ofdetergent therein, thereby causing certain portions to be less effectiveor even unsatisfactory in dry cleaning performance.

According to the invention herein, there are provided stable,concentrated dry cleaning compositions which comprise a coupling agent,essential to achieve stability against phase-separation. The termcoupling agent, as used herein, generally refers to water-solubleorganic compounds which are soluble both in the dry cleaning solvent andin water; such agents function herein to couple or link water present inthe composition (including detergent solubilized therein) with thesolvent to provide and maintain concentrated compositions generallystable against phase separation.

Examples of coupling agents, suitable for use in the concentratedcompositions herein, are known in the art and are readily availableitems of commerce. Suitable coupling agents include e.g., lower ethyleneglycol-monoalkyl ethers and lower monohydroxy alkanols; lower, as usedherein and in the appended claims, generally refers to those ethers andalcohols wherein the monoalkyl and alkanol contains from one to about 4carbon atoms. Specific examples of such compounds include, e.g., thefollowing:

ethyleneglycol-monomethyl ether; ethyleneglycol-monoethyl ether;ethyleneglycol-monopropyl ether; ethyleneglycol-monobutyl ether;methanol;

ethanol;

n-propanol;

isopropanol;

n-butanol; and

t-butanol.

Coupling agents, preferred herein for performance on freeze-thawstability, for convenience in handling, and for economical reasons,include isopropanol and ethyleneglycol-monobutyl ether (availablecommercially under the trade name Butylcellosolve).

The amount of a coupling agent employed in a concentrated dry cleaningcomposition herein generally ranges from about 0.25% to about 0.75% byweight of the composition. Within this range, an amount of couplingagent can be employed to couple essentially all water normally presentin the concentrated compositions herein.

Because substantially all of the water present is carried over into theconcentrated composition along with the detergent, the specific amountof coupling agent employed generally depends upon the amount ofdetergent used in the composition. For example, a concentratedcomposition containing about 40% by weight detergent generally containsabout 0.3% by weight water; similarly, concentrated compositionscontaining lower or higher detergent concentrations generally containproportionately lower or higher amounts of water, respectively.

Accordingly, the amount of coupling agent, which suffices to couple thewater generally present in a concentrated composition containing a givendetergent concentration in the range herein, bears a directlyproportional relationship to the amount of detergent. This relationship,expressed as a weight ratio of detergent to coupling agent, is at leastabout :1. Thus, e.g., a detergent concentration of about 40% by weightnecessitates the use of at least about 0.5% of a coupling agent to linkor couple the 0.3% by weight water generally present in such aconcentrated composition; similarly, detergent concentrations of about20% and about 60% by weight generally require the use of at least about0.25% and at least about 0.75% by weight coupling agent, respectively.

The concentrated compositions of the invention herein further comprisefrom about 20% to about 60%, preferably (for processing and handlingreasons) about 40%, by weight of an anionic organic synthetic detergentwhich comprises the monoethanolamine salts of an essentially pure, broadcut, linear alkyl (from about C to C benzene sulfonic acid, i.e.,MEA-LAS. Above about 60% by weight, the concentrated composition becomesa stiff paste which, of course, is not prone to phase-separation. Withregard to the detergent additive used herein, the alkyl, as termedherein and in the appended claims, is a mixture of alkyls having anaverage chain length of from about 8 to about 18 carbon atoms. For bestresults, the alkyls herein, preferably, have at least about 4 differentcarbon chain lengths, each of which contains from about 6 to about 20carbon atoms, wherein at least about 80% by weight of the chain lengthsare within the range of from about 8 to about 18 carbon atoms andwherein at least two of the chain lengths comprise at least about 20% ofthe alkyl. In the trade, such mixed alkyls are often termed broad cuts;thus, for example, a broad cut C or dodecyl benzene sulfonic acid(particularly prefcrrcd herein) has a mixture of alkyls having anaverage chain length of about 12 (specifically between 11 and 12) carbonatoms, specifically consisting essentially of (percent is by weight):

C from to about 0.4%

C from about 17% to about 19.9% C from about 40.6% to about 42.8% C fromabout 29.4% to about 32.7% C from about 6.6% to about 9.1% C from about0.2% to about 0.23%

Similarly, broad cut C (octyl) and C (octadecyl) benzene sulfonic acidshave a mixture of alkyls having an average chain length of about 8 and18 carbon atoms, respectively.

When the monoethanolamine salt of an alkyl benzene sulfonic acidcomprising a mixture of linear alkyl carbon chain lengths (i.e., a broadcut, linear alkyl benzene sulfonic acid) is employed as a detergentadditive in the concentrated dry cleaning compositions herein, use levelcompositions derived therefrom generally exhibit an improved level offabric cleaning and a reduced level of fabric graying in comparisonwith, e.g., a pure cut, linear alkyl benzene sulfonic acid (i.e., one inwhich the alkyl does not contain a mixture or distribution of variouscarbon chain lengths, but, instead, has only one alkyl having a definiteand fixed carbon chain length).

Suitable broad cut, linear alkyls for use in compositions herein includethose wherein the chain lengths average from about 8 to about 18 carbonatoms; specific examples of such compounds include, e.g.,monoethanolamine salts of broad cut, linear octyl, nonyl, decyl,undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,heptadecyl, and octadecyl benzene sulfonic acid wherein the chainlengths average about C C C C C12, C C14, C C C and C carbon atoms,respectively.

Methods which can be used to prepare the detergents employed in thecompositions herein are generally known in the art. For example, asuitable method comprises, firstly, reacting a linear, paraffinichydrocarbon (e.g., a petroleum distillate) containing a mixture ofalkyls having a desired carbon chain length within the range of fromabout 8 to about 18 carbon atoms with chlorine under conventionalmethods to obtain the chlorinated broad cut, linear hydrocarbon which isthereafter reacted with benzene (e.g., under Friedel-Crafts reactionconditions) to obtain the broad cut, linear alkyl benzene; the lattercompound can alternatively be prepared by reacting the linear,paraffinic hydrocarbon with benzene with, e.g., hydrofluoric acid. Thebroad cut, linear, alkyl benzene is thereafter sulfonated, preferably,with sulfur trioxide to form the broad cut, linear, alkyl benzenesulfonic acid which is thereafter neutralized, e.g., by mixing equimolaramounts of monoethanolamine and the alkyl benzene sulfonic acid to forma monoethanolamine alkyl benzene sulfonate employed as a detergentadditive herein.

The broad cut, linear, alkyl benzene sulfonic acids (or theirmonoethanolamine salts) employed herein are essentially pure.By-products, which can result when certain methods are used to sulfonatean alkyl benzene (broad or pure cut) generally inhibit fabric cleaningand/ or promote undesirable fabric graying despite the fact that suchbyproducts, especially those occurring after the neutralization step,may themselves be otherwise suitable detergents.

By way of brief explanation, one commonly used sulfonation methodcomprises reacting an alkyl benzene with chlorosulfonic acid inaccordance with the following unbalanced reaction:

(1) R CISOSH R t manates; Unless the resulting alkyl benzene sulfonicacid is purified of the large amount of other reaction by-products,subsequent neutralization of the reaction products will yield thedesired MEA-LAS detergent and other neutralization by-products whichgenerally inhibit dry cleaning performance of the compositions herein.Thus, for example, when the products of reaction (1) are neutralizedwith monoethanolamine (MBA), in accordance with reaction (2), thereaction products include an MEA- LAS detergent and an MBA alkyl benzenesulfonamide plus other MEA salt by products; unless removed, thepresence of the sulfonamide (itself an often used detergent) in thecompositions herein generally inhibits their dry cleaning performance.

R SO3NH3CH2CH2OH R-qS-SO2C1 (MEA-LAS) HzN CHZCHQO H (MEA) RR-zlx-SOz-NHOHrCHzOI-I (MEA alkyl benzene sulionamide) M EA saltlay-products The presence of such by-products is generally avoided when,e.g., the above-described preferred sulfonation procedures are used;alternatively, such by-products, when formed, e.g., from the use ofreaction (1) above as a method of sulfonation, can conveniently beremoved after their formation by techniques known in the art, e.g., bythe use of ion exchange resins. It is not desirable, for economical andpractical reasons, to neutralize the alkyl benzene sulfonic acid in thepresence of such byproducts as are formed in reaction (1) above;however, if desired, neutralization can be so accomplished and theresulting by-products (e.g., the sulfonamide in reaction (2) above) canthereafter be removed by conventional techniques, e.g., by the use ofion exchange resins prior to formulating the MEA-LAS into a compositionherein.

The compositions of the invention herein use the monoethanolamine saltof the alkyl benzene sulfonic acids. Only the monoethanolimaine .(MEA)salt of the linear alkyl benzene sulfonic acids herein provides adetergent which, when incorporated into chlorinated dry cleaningsolvents (preferred herein), achieves a preferred singlephase drycleaning composition; other alkanolamine salts (e.g., dimethanolamine,diethanolamine, triisopropanolamine, and the like) of the alkyl benzenesulfonic acids employed herein provide detergents which generally areeither less effective in performance or undesirably result inunfilterable two-phase dry cleaning compositions.

It has been found, however, that other alkanolamines can be employed inadmixture with MEA to form salts of the broad cut, linear, alkyl benzenesulfonic acids used herein, which detergents, when utilized assubstitutes for MEA-LAS, achieve effective single-phase dry cleaningcompositions. Examples of such other alkanolamines which are suitablefor use in admixtures with MBA, include, e.g., the mono-, di-, andtri-alkanolarnines wherein the alkanol is methanol, propanol,isopropanol, and butanol the diand tri-alganolamines wherein the alkanolis ethanol, and mixtures thereof. Specific examples of such compoundsare as follows:

monomethanolamine; dimethanolamine; trimethanolamine; monopropanolamine;dipropanolamine; tripropanolamine; monoisopropanolamine;diisopropanolamine; triisopropanolamine; monobutanolamine;dibutanolamine; and, tributanolamine.

Specific examples of preferred alkanolamines for use in admixtures withMEA include diethanolamine (DEA), triethanolamine (TEA), andmonoisopropanolamine (IPA).

Any one or more of the foregoing other alkanolamines can be employed inadmixture with MEA. When any of such other alkanolamines are employed inadmixture with MEA, the amounts in which they can be admixed will varydepending upon the specific other alkanolamine or alkanolamines beingused. Generally, suflicient MEA should be used in the admixtures toprovide filterable use level dry cleaning compositions; i.e., finelydispersed, homogenous or, preferably, single-phase detergent additivedry cleaning compositions; for example, an admixtue of MEA with up toabout 90% by weight IPA, with up to about 80% by weight DEA, or with upto about 40% by weight TEA provides detergent additive dry cleaningcompositions which generally are single-phase.

Accordingly, the detergent additive of the compositions herein canfurther comprise an alkanolamine salt of an essentially pure, broad cut,linear alkyl benzene sulfonic acid employed herein, wherein thealkanolamine consists essentially of an admixture of from about to about99% by Weight monoethanolamine and from about 1% to about 90% by weightof one or more other alkanolamines selected from the group consistsingof (A) mono, di-, and tri-alkanolamines wherein the alkanol is methanol,propanol, isopropanol, and butanol, (B) diand trialkanolamines whereinthe alkanol is ethanol, and (C) mixtures thereof.

The concentrated dry cleaning compositions herein further comprise a drycleaning solvent in which the detergent and coupling agent arecontained. Suitable dry cleaning solvents for use in the concentratedcompositions herein include those commonly referred to as chlorinatedsolvents and hydrocarbon solvents, as well as mixtures thereof.

Specific examples of suitable chlorinated solvents inelude, e.g.,trichloroethylene, carbon tetrachloride, methyl chloroform, andperchlorethylene; for economical and other reasons and for handlingconvenience, preferred chlorinated solvents are methyl chloroform andper chlorethylene, particularly the latter.

Specific examples of suitable hydrocarbon solvents include, e.g.,Stoddards solvent, naphtha, 140 solvent, kerosene, gasoline, mineralspirits, mineral oil, and aromatic hydrocarbons (e.g., benzene, toluene,xylene, or mixtures thereof); for economical reasons, preferredhydrocarbon solvents are the aromatic hydrocarbons, particularlymixtures of benzene, toluene, and xylene.

Generally, the concentrated compositions herein have a pH within therange of from about 6.5 to about 9; the pHs herein and in the appendedclaims are determined with concentrated compositions diluted to about0.6% by weight detergent concentrations and at a 75% solvent relativehumidity. Below a pH of about 6.5, the compositions tend to be tooacidic and can cause corrosion and other undersirable effects; above apH of about 9, the compositions can have an undesirable effect on fabricdyes, especially acid-set dyes.

The concentrated dry cleaning compositions herein require dilution withadditional solvent in order to obtain use level compositions whichimprove dry cleaning performance and which, desirably, are filterableand, therefore, advantageously employed with filtration apparatusconventionally used in the industry. To be filterable, the use levelcomposition should be a finely dispersed, homogeneous emulsion or,preferably, single-phase; to this end, the dry cleaning solvent selectedfor use in the concentrated compositions herein becomes important.

With regard to use level compositions derived from the concentratedcompositions herein, hydrocarbon solvents are generally unsuitable foruse as a major component thereof with the detergent additive employedherein and when used, generally result in compositions (use level) whichundesirably are not filterable and/or are not satisfactory in drycleaning performance. Accordignly, to be filterable, the concentratedcompositions herein should be diluted with a chlorinated dry cleaningsolvent, particularly perchlorethylene, regardless of the solventemployed to formulate the concentrated compositions herein. Because therequired dilution necessitates the addition of large amounts of thechlorinated solvent, the use level composition resulting from aconcentrated composition herein employing a hydrocarbon solvent willgenerally be in the form of a filterable finely dispersed, homogeneousemulsion which contains only a low amount of the hydrocarbon solvent andwhich, to the naked eye, generally appears as a single-phase; generally,the amount of hydrocarbon solvent present in such a use levelcomposition will be about 20% by Weight of the composition or less andabout 27% by weight of total solvent or less. For example, by adding asufficient amount of a chlorinated solvent to a concentrated compositionwhich consists essentially of about 20% by weight MEA-LAS (C and aboutby weight hydrocarbon solvent, e.g., a mixture of benzene, toluene, andxylene, a filterable use level composition can be achieved whichconsists essentially of about 5% by weight MEA-LAS (C and about byweight solvent wherein the solvent is an admixture of the chlorinatedsolvent and the hydrocarbon solvent, specially about 75% by weight (ofthe composition) chlorinated solvent and about 20% by weight (of thecomposition) hydrocarbon solvent, the hydrocarbon solvent being about27% by weight of the chlorinated solvent or about 21% by weight of totalsolvent; diluting the concentrated composition to lower detergentconcentrations provides use level compositions having smaller amounts ofthe hydrocarbon solvent. Preferably, the solvent employed in theconcentrated compositions herein is a chlorinated dry cleaning solvent,particularly perchlorethylene, in which event the use level compositionsobtained after diluting such concentrated compositions with, e.g.,additional perchlorethylene are single-phase.

The concentrated dry cleaning compositions of the invention hereinshould be diluted with a sufiicient amount of chlorinated dry cleaningsolvent to provide use level compositions consisting essentially of fromabout 0.06% to about 5%, preferably about 0.3%, by weight detergent andfrom about 95% to about 99.94%, preferably about 99.7%, by weightsolvent. The use level composition, because of the coupling agentemployed in the concentrated dry cleaning compositions herein, willadditionally contain the coupling agent therein; however, the weightpercentage of the coupling agent in the use level composition is quitesmall and insignificant, inasmuch as its presence in the use levelcomposition is neither essential nor deleterious to the achievement of afilterable dry cleaning composition with improved dry cleaningperformance.

A particularly preferred concentrated dry cleaning composition hereinconsists essentially of about 40% by weight MEA-LAS (C about 0.5% byweight isopropanol, and about 59.5% by weight perchlorethylene, whereinthe composition has a pH of about 7. This composition generally exhibitsprolonged stability against phase-separation under severe conditions oftemperature and excellent freeze-thaw recovery and stability; moreover,this concentrated composition can conveniently be diluted withadditional perchlorethylene to provide a use level compositionconsisting essentially of about 0.3% by weight MEA-LAS (C and about99.7% by weight perchlorethylene (and, insignificantly, a minor amountof isopropanol), which use level composition is single-phase andgenerally achieves high levels of fabric cleaning and low levels offabric graying.

Optionally, the concentrated compositions herein can additionallycontain one or more of a variety of other fabric treating agents whichare soluble in the dry cleaning solvent. Examples of such agents, whichare especial- 1y desirable for inclusion herein, are, e.g., brighteners(which can be nonionic or cationic and, preferably, are of the anionicstilbene-derivative types), perfumes, antistatic agents, fabricsoftening agents, and germicides. Generally, the amounts of such agents(e.g., brighteners and perfumes) employed herein are quite small andrange from about 0.01% to about 3% by weight of a concentrated levelcomposition herein; larger amounts can, if desired, be used. Afterdilution to a use level composition, the amount of such agents generallyranges from about 0.0001% to about 0.03% by weight of the use levelcomposition.

The following examples will serve to further illustrate the invent-ionherein and it will be understood that said examples in no way limit theinvention.

The examples herein generally illustrate, by way of comparison, thestability of the concentrated level compositions herein and the improveddry cleaning performance achieved by use level compositions derivedtherefrom.

Unless otherwise noted, the comparison tests performed therein, briefly,involved the following procedure:

Test swatches (4" x 4") are cut from bleached, mercerized cotton printcloth. For each test, 18 swatches are used; nine are clean or unsoiledswatches and nine are each soiled with an insoluble soil commonlyreferred! to as rug-beater soil. Four readings of each swatch, clean andsoiled, are then taken on a reflectometer to obtain its originalreflectance (Ro) using an 81.4 percent reflectance backplate (Filter G)with the swatches being read in nine layers (i.e., swatches are backedby sufficient fabric, which is washed in the reference composition, tomake nine layers). The swatches are thereafter placed into a relativehumidity (R.H.) conditioner and conditioned for at least 36 hours over asaturated sodium acetate solution at 75% RH. and about 75 F. Three cleanand three solid swatches are then placed into each of three 500' ml.Launder-Ometer cans along with 30 stainless-steel balls and 150 ml. of adry cleaning composition having a measured weight concentration ofdetergent as measured at 75% RH. by conventional techniques. Each can,with its contents, is then placed into the Launder-Ometer and run forone hour, after which each can is removed, the swatches drained andseparated by pouring the contents through a funnel, and the swatchesdipped about times in clean perchlorethylene. The swatches arethereafter placed on a blotter and allowed to dry, after which eachswatch is again similarly read on the reflectometer to obtain its finalreflectance (R Cleaning performance is calculated using the averageoriginal and final reflectances for the nine soiled swatches inaccordance with the equation:

R;Ra (reference composition) Graying (G) is calculated using the averageoriginal and final reflectances for the nine clean swatches inaccordance with Equation 3 above. Overall dry cleaning performance isthen determined by dividing the cleaning performance (C) by the grayingperformance (G) to obtain the C/ G ratio.

The reference composition referred to above and employed in the examplesfor comparative purposes, is one generally used as a standard in theindustry and is a dry cleaning composition consisting essentially ofabout 99.4% by weight perchlorethylene as the solvent and about 0.6% ofa detergent consisting essentially of sodium di-n-octyl sulfo-succinate.This composition makes an excellent standard because the detergent is arelatively pure chemical compound available in 100% pure grade; thecomposition has been assigned a C value of 1, a G value of 1 and a C/Gratio of 1.

Unless otherwise noted in the examples, all percentages and parts are byweight. Generally, a difference of 10% or better between C/ G ratios isconsidered significant, in accordance with recognized grading practicein the industry. Variations in C/ G ratios of any single compositionrepeatedly appearing in the following examples is generally due to thevarying soil loads of the test swatches and/ or to experimental error.Generally, higher C/ G ratios reflect both better fabric cleaning andlower fabric graying.

EXAMPLE I Thirty-five concentrated dry cleaning compositions, having apH of about 8, were prepared consisting essentially of perchlorethylenecontaining about 40% of an essentially pure, broad cut MEA-LAS (Canionic detergent additive; the compositions, each of which additionallycontained about 0.3% water carried over into the compositions along withthe detergent additive, were then divided in 5 groups of seven. To thefirst group (Group #1) was then added about 0.5% isopropanol (IPA); tothe second was added about 1% IPA; to the third, about 1 /2% IPA; and,to the fourth group, about 2% IPA, The fifth group (Group 5) was notprovided with IPA and was, therefore, used as a reference or blank.

One sample from each of the five groups was then allowed to situndisturbed at 0, 10, 30, 40, 50, 70, and at room temperature (about 75temperatures are in degrees Fahrenheit.

In less than three days, each of the seven samples of the fifth group(i.e., the blank) were visually noted to have separated into aqueous andorganic phases; moreover, those samples stored at temperatures of about40 F. or below exhibited unsatisfactory freeze-thaw stability and didnot recover.

All the samples of the remaining four groups did not exhibitphase-separation even after a testing period of about one month,indicating the effective coupling function achieved in the concentratedcompositions herein.

EXAMPLE II To further illustrate the undesirable effects of carried overwater present in the concentrated dry cleaning compositions, threeconcentrated compositions consisting essentially of perchlorethylenecontaining, respectively, about 46%, about 42%, and about 40%essentially pure, broad cut MEA-LAS (C were prepared and each dividedinto three samples. A sample of each composition was tested forstability at various conditions indicated by the following results.

The 46% detergent composition samples were cloudy at room temperature(about 75 F.) as well as at lower temperatures and did not recover orreassume a singlephase after vigorous shaking. The 42% detergentcomposition samples were all clear and single-phase at room temperaturebut did not exhibit freeze-thaw recovery to a clear, single-phasecomposition after overnight storage at a temperature of about 40 F. The40% detergent composition samples were clear and single-phase at roomtemperature and exhibited satisfactory freeze-thaw recovery afterstorage at about 40 F. for three days; however, these samplessubsequently (at about one week) exhibited phase-separation and wereunable to recover at temperatures of about 70 F. or lower.

When, however, isopropanol or ethyleneglycol-monobutyl ether is added ina similar amount to similar concentrated composition samples (pH about8) and similarly tested, the samples are generally stable againstphaseseparation and exhibit satisfactory freeze-thaw recovery even afterprolonged storage.

EXAMPLE III A concentrated composition (pH about 8) herein, consistingessentially of perchlorethylene containing about 1 1 40% essentiallypure, broad cut MEA-LAS (C and about 0.5 isopropanol, was prepared; thecomposition was tested for stability as described in Example I andresults of the test were similar to those of IPA-containing compositionstherein.

The composition was then diluted with additional perchlorethylene toobtain a single-phase use level dry cleaning composition (Composition A)having a pH about 7 and consisting essentially of about 0.3% MEA-LAS (Cand about 99.7% perchlorethylene and additionally containing a smallamount of isopropanol; this composition was then tested for dry cleaningperformance in accordance with the comparison test procedures describedin the foregoing discussion.

Other use level compositions employed in the comparison tests wereComposition B and Composition C, as follows:

The results, relative to the Reference Composition, are as follows:

Composition: C/G ratio Reference Composition 1.00 A 3.87 B 3.90 C 3.39

The results indicate the stability achieved by employing a couplingagent in the concentrated compositions herein and further demonstratethat the concentrated compositions herein can be diluted with a suitablechlorinated solvent to achieve use level compositions in which thecoupling agent is not essential and does not harm the improved drycleaning performance generally obtained therewith.

EXAMPLE 1V When the procedure of Example III was repeated, substitutingethyleneglycol-monobutyl ether for the isopropanol used therein, theresulting concentrated compositions was similarly stable againstphase-separation and a similar use level composition derived therefromachieved similarly improved dry cleaning performance, specificallycalculated as a C/G ratio of about 3.88.

EXAMPLE V The concentrated compositions of the invention herein and uselevel compositions derived therefrom are advantageously suitable for thedesirable incorporation of optional additives. Suitable dry cleaningcompositions (pH about 7) of the invention herein, which compositionscontain a perfume and a brightener, consist essentially of about:

(a) Use level composition Percent MEA-LAS (C 0.3 Isopropanol 0.005Perchlorethylene 99.6928 Perfume 0.002 Anionic brightener 0.0002

12 (b) Concentrated level composition Percent MEA-LAS (C 40 Isopropanol0.5 Perchlorethylene 59.23 Perfume 0.25 Anionic brightener 0.02

When, in any of the foregoing examples, the MEA salt of an essentiallypure, broad cut, linear octyl, nonyl, decy], undecyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl, or octadecyl benzenesulfonic acid is substituted for the C MEA-LAS employed therein, resultssimilar to those therein are obtained.

Similarly, when in any of the foregoing examples, the HEA employed inthe C MEA-LAS therein is substituted with an admixture of alkanolaminesconsisting of about 20% by weight MBA and about by Weight DEA orconsisting of about 60% by weight MBA and about 40% by weight TEA,results similar to those reported therein are obtained.

Similarly, when in any of the foregoing examples, the perchlorethyleneemployed therein is substituted with methyl chloroform, results similarto those obtained therein are achieved. When the perchlorethyleneemployed therein is substituted with a mixture of benzene, toluene, andxylene, the resulting concentrated compositions are similarly stableand, after dilution, provide use level compositions which are finelydispersed, homogeneous emulsions and which similarly achieve improveddry cleaning performance.

Having described the invention in detail, what is now claimed is:

1. A concentrated dry cleaning composition which is stable against phaseseparation, said composition consisting essentially of (A) from 20% toabout 60% by weight of an anionic detergent which consists essentiallyof an essentially pure, broad cut, linear alkyl benzene sulfonic acid,which has been neutralized with monoethanolamine and which issubstantially free of alkyl benzene sulfonamide and monoethanolaminesalt by-products, and wherein said alkyl in said alkyl benzene sulfonicacid is a mixture of alkyls having an average chain length of from about8 to about 18 carbon atoms,

(B) from about 0.25% to about 0.75% by weight of a coupling agentselected from the group consisting of ethylene glycolmonalkyl etherswherein the monoalkyl group contains from 1 to about 4 carbon atoms, andmonohydroxy alcohols containing from 1 to about 4 carbon atoms,

(C) and the balance a chlorinated dry cleaning solvent. said compositionhaving a pH within the range of about 6.5 to about 9, and wherein theweight ratio of said detergent to said coupling agent is at least about80:1.

2. A concentrated dry cleaning composition in accordance with claim 1,said composition consisting essentially of about 40% by weight ofcomponent (A), wherein the alkyl is a mixture of alkyls having anaverage chain length of between 11 and 12 carbon atoms, about 0.5% byweight of isopropanol, about 0.25% by weight perfume, about 0.02% byweight brightener, and about 59.23 by weight perchlorethylene.

3. A concentrated dry cleaning composition in accordance with claim 1,wherein said coupling agent is selected from the group consisting ofethyleneglycol-monobutyl ether and isopropanol.

4. A concentrated dry cleaning composition in accordance with claim 3,wherein said composition consists essentially of said solvent containingabout 40% by weight of said detergent and about 0.5% by weight of saidcoupling agent.

5. A concentrated dry cleaning composition in accordance with claim 4,wherein said solvent is selected from the group consisting of methylchloroform and perchlorethylene.

6. A concentrated dry cleaning composition in accordance with claim 5,wherein said solvent is perchlorethylene.

7. A concentrated dry cleaning composition in accordance with claim 6,wherein said alkyl is a mixture of alkyls having an average chain lengthof about 12 carbon atoms.

8. A concentrated dry cleaning composition in accordance with claim 7,wherein said pH is about 7.

References Cited UNITED STATES PATENTS 2,271,635 2/1942 Flett 8-142X3,013,973 12/1961 Bennett 25249.5X

1 4 3,222,286 10/1962 Barnes 252-l71 X 3,310,498 3/1967 Michaels et a18-142 X 3,310,499 3/ 1967 Michaels et al 8142 X 3,349,038 10/1967Michaels et a1 252161 3,484,379 12/1969 Mankowich 25216l X OTHERREFERENCES Bennett: The Chemical 'Formulary, vol. I. p. 79, 1933.Gregory: Use and Applications of Chemicals and Re- 0 lated Materials,1939, p. 331.

Cellosolve and Carbitol Solvents-Glycol Ethers, Union CarbideCorporation, 1962, p. 7.

LEON D. ROSDOL, Primary Examiner 15 H. A. PITLICK, Assistant ExaminerUS. Cl. X.R.

Po-ww UNITED STATES PATENT OFFICE CERTIFICATE OF CDRRECTION Patent NO3,642,644 Da'ted February 15, 1972 Herbert E. Grote and Wilbur G. HenryInventor(s) It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 9, line 55, delete "Ra" and insert therefor Ro Column 9, line 57,delete "Ra" and insert therefor Ro olumn 12, line 19, delete "HEA" andinsert therefor MBA column line delete g yfiolmonalkyl" and inserttherefor glycolmonoalkyl Signed and sealed this L .th day of July I972.

(SEAL) Attest: I

EDWARD M.FLEICHER,JR. ROBERT GOT'ISCHALK Att eating Officer ICommissioner of Patents

